From: Paul Furman on
DanP wrote:
> On 22 May, 23:17, Paul Furman <pa...@-edgehill.net> wrote:
>
>> Theoretically but in reality it's the opposite given a budget. BTW this
>> is not the same discussion as the OP regarding sensor size and
>> equivalent fields of view. I'm not even sure what this part of the
>> thread is discussing <g>.
>
> To be on topic again, I think the NEX-5 looks ridiculous with the
> 18-55mm lenses on.
> I mean it is pointless to have a smaller camera without smaller
> lenses.
>
> So I have asked myself, what will be lost by making the lenses
> smaller.
> The answer to that is the lenses will be slower.

Also, what will be gained by making them smaller. In this case, the only
price is coolness factor but I'd dispute that. Look at these rangefinder
lenses on Panasonic's equivalent micro 4/3:
http://www.pbase.com/image/121902428/original.jpg
context: forum.getdpi.com/forum/showthread.php?p=186390

Also by reducing size, you lose autofocus & image stabilizing. It would
be possible to chip such a lens to report f/stop & focus distance for
flash metering & lens correction software but these cameras are targeted
to the mass market so AF is essential. A decent viewfinder isn't
unfortunately.
From: DanP on
On May 23, 3:31 am, rfisc...(a)sonic.net (Ray Fischer) wrote:

> Wrong.  Bigger apertures allow higher resolution.  That's why big
> telescopes are better than tiny ones.

Telescopes are focused at infinity so that is a different case.
Binoculars are better big but with the size it comes a smaller DOF.

This is the same in cameras if the lens are set to maximum aperture
(low f number).
But the bigger the size of the lens the smaller the internal aperture
has to be to keep the same f number.


DanP
From: RichB on
On Sat, 22 May 2010 22:51:14 -0700 (PDT), DanP <dan.petre(a)gmail.com> wrote:

>On May 23, 3:31�am, rfisc...(a)sonic.net (Ray Fischer) wrote:
>
>> Wrong. �Bigger apertures allow higher resolution. �That's why big
>> telescopes are better than tiny ones.
>
>Telescopes are focused at infinity so that is a different case.
>Binoculars are better big but with the size it comes a smaller DOF.
>
>This is the same in cameras if the lens are set to maximum aperture
>(low f number).
>But the bigger the size of the lens the smaller the internal aperture
>has to be to keep the same f number.
>
>
>DanP

Hey everyone, has this DanP numb-nuts ever gotten anything right yet?

From: Paul Furman on
DanP wrote:
> the bigger the size of the lens the smaller the internal aperture
> has to be to keep the same f number.

The opposite.
From: DanP on
On May 23, 7:31 am, Paul Furman <pa...@-edgehill.net> wrote:
> DanP wrote:
> > the bigger the size of the lens the smaller the internal aperture
> > has to be to keep the same f number.
>
> The opposite.

Can you argue why?

If you are right then it means for the same f number more light is let
in by bigger lenses, first by the lenses then by the aperture.
And another consequence will be that DOF for bigger size lenses will
be even smaller, bigger lenses will scatter more light and bigger
aperture will make it even less sharp.

By aperture I mean the size of the diaphragm measured in inch/mm. For
the purpose of comparing apples to apples f number has to be kept the
same.


DanP
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